Diabetes is one of the most prevalent chronic diseases in the United States, and it is a leading cause of death. Persons with diabetes are at risk for major complications, including diabetic ketoacidosis, end-stage renal disease, diabetic retinopathy and amputation. There are also a host of less directly related conditions, such as hypertension, heart disease, peripheral vascular disease and infections, for which persons with diabetes are at substantially increased risk. Accordingly, new methods of treating diabetes and diseases or conditions associated with abnormal glucose metabolism are needed.